I'd been getting SMART notifications for the same "Current Pending Sector" for days.
The dd solutions around weren't resolving anything (they'd appear to zero data and re-write it but didn't effect the smart status). Be warned, I am no guru on this,
just cargo-culting commands from forums.

I didn't get any read/write errors with any these command, so the absence of errors
may just be the drive is able to effectively cover them up somehow.

Also, running the dd ones again would appear to restore the data,
but even then the hdparm --read-sector would show zeros.
I'm interpreting this as the hdparm talking to the drive at a lower level
and forcing the Pending writes, but dd just sees the drives remapped results...
is that what could be going on?